Posted
by
samzenpus
on Wednesday October 20, 2010 @09:36PM
from the old-neighborhood dept.

The Bad Astronomer writes "Astronomers using Hubble Space Telescope have found a galaxy at the very edge of the Universe: the light from this far-flung object has been traveling a whopping 13.1 billion years to get here! The galaxy appears as a non-descript dot in the infrared Hubble Ultra Deep Field taken using the Wide Field Camera 3, but a spectrum taken using a ground-based telescope confirms that we're seeing this object as it was a mere 600 million years after the Big Bang itself."

I think there's a maximum length after which a galaxy cannot exist; diminishing element returns from supernovae. Unfortunately I'm not sure how long it is, but it's much longer than 13 billion years; individual red dwarves can last for hundreds of billions of years. As for merger with other galaxies or destruction by a supermassive black hole though, its anyone's guess.

When the universe was still too hot for atoms to form, photons couldn't get too far before hitting a free electron. Then the universe cooled enough for recombination of hydrogen ions and electrons, making the universe 'clear'.

So we can only see back to 377000 years after the big bang, then it's lost in the background microwave radiation.

This question is not well phrased. There is no universal "now" in relativity. You probably mean something like "in our reference frame does this galaxy exist somewhere now", and then the answer is that we can't tell. If you'll choose some other reference frame, you'll get different points to correspond to our "now". So abandon the notion of "still exist", it exists "now" in the most meaningful way, the point we see when we look there...

Considering the article estimates the bing bang to have happend around 13.7 billion years ago, I don't see how red dwarves can exist for over 100 billion years.

Observe a red dwarf over a period of years and estimate its current mass as well as its rate of mass depletion. Then do the math and calculate the amount of time it will take until its mass is such that it is no longer a red dwarf. Obviously someone has done this and come up with an estimated longevity of more than 100 billion years.

No, the grandparent's point is that for all intents and purposes, we only experience something else as existing by signals exchanged at the speed of light (the basic point of special relativity). Whether or not an object exists "right now" is sorta a meaningless question to ask in the first place.

You might be tickled to learn that there are some (wild-ish) theories that posit "every mathematical abstraction exists", as in, for every concept you can derive from mathematics, it actually exists "somewhere". Look at "mathematical multiverse" here http://space.mit.edu/home/tegmark/crazy.html [mit.edu] And Tegmark is not actually a crackpot, just fanciful.:)

In a way it is. Everything is. The cosmic background radiation simply has so much redshift it's shifted to microwave (redshift of over 1000). WMAP [nasa.gov] has made a picture. Note that this glow isn't from the Big Bang itself. The universe was so hot (over a billion K) it wasn't transparent yet. There were no protons and neutrons, only a superheated quark soup. The signal WMAP captured was from about 400.000.000 years later: when the universe expanded and cooled enough to get transparent.

The light has traveled for 13.1 billion years while the universe has kept expanding.The galaxy is now 3 times that distance from us.sheesh call yourselves nerds....see ned wrights tutorial here:http://www.astro.ucla.edu/~wright/cosmolog.htm

Yes. The fluctuations in density seen in the cosmic microwave background are large enough that some can collapse under gravity to galaxy massed globs within a few hundred million years. What has been more of a mystery is how stars can form since gas needs to cool to condense enough to form stars and big bang gas is very clean and has a hard time cooling radiatively. One might think that only very massive stars might form but then this would never dirty up the gas since they would soon collapse to back holes and never release processed material back to their surroundings. However, pair instability supernovae disrupt their cores when they explode and likely seed protogalaxies particularly with oxygen which, when combined with abundant hydrogen, can form ice and allow normal cooling of gas for star formation. One bit of evidence that ice is important comes from the infrared emission of an early quasar: http://adsabs.harvard.edu/abs/2008ApJ...686..251D [harvard.edu]

Actually, what you mean is the edge of the observable universe. If any of the inflationary models are correct there may be way, way more universe out there beyond this little blob of light, they're just cut off from observation here because the light from them hasn't had time to reach us since the inflationary phase ended. If, as is probably the case, we're in another phase of accelerating inflation, we'll never see beyond this horizon because the space between here and there is expanding faster than the speed of the light, so it'll never get here.